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ludc web

João Vieira

Doctoral student

ludc web

Phenolic wastewaters depuration by electrochemical oxidation process using Ti/IrO2 anodes

Author

  • Ana S Fajardo
  • Helga F Seca
  • Rui C Martins
  • Vanessa N Corceiro
  • João P Vieira
  • Emília Quinta-Ferreira
  • Rosa Quinta-Ferreira

Summary, in English

The electrochemical oxidation (EO) of phenolic wastewaters mimicking olive oil mill effluents was carried out in a batch stirring reactor using Ti/IrO2 anodes, varying the nature (NaCl and Na2SO4) and electrolyte concentration (1.8-20 g L-1), current density (57-119 mA cm(-2)) and initial pH (3.4-9). Phenolic content (TPh) and chemical oxygen demand (COD) removals were monitored as a function of applied charge and over time. The nature of the electrolyte greatly affected the efficiency of the system, followed by the influence of the current density. The NaCl concentration and the initial pH influenced the process in a lesser extent. The best operating conditions achieved were 10 g L-1 of NaCl, current density of 119 mA cm(-2) and initial pH of 3.4. These parameters led to 100 and 84.8% of TPh and COD removal, respectively. Under these conditions, some morphological differences were observed by SEM on the surface of the anode after treatment. To study the potential toxicity of the synthetic effluent in neuronal activity, this mixture was applied to rat brain slices prior to and after EO. The results indicate that although the treated effluent causes a smaller depression of the neuronal reactive oxygen species (ROS) signal than the untreated one, it leads to a potentiation instead of recovery, upon washout. Furthermore, the purification of a real olive mill wastewater (OMW), with the organic load of the synthetic effluent, using the same optimised operating conditions, achieved total phenolic compounds abatement and 62.8% of COD removal.This study demonstrates the applicability of this EO as a pre-treatment process of a real effluent, in order to achieve the legal limit values to be discharged into natural streams regarding its organic load.

Publishing year

2017-03-01

Language

English

Pages

7521-7533

Publication/Series

Environmental Science and Pollution Research

Volume

24

Issue

8

Document type

Journal article

Publisher

Springer

Topic

  • Environmental Sciences
  • Other Electrical Engineering, Electronic Engineering, Information Engineering

Status

Published

ISBN/ISSN/Other

  • ISSN: 1614-7499